Postcyclic behavior of low-plasticity silt

Author

Shuying Wang

Abstract

"Liquefaction of low-plasticity silt has been reported during earthquakes in the recent past. Excess pore pressure builds up due to the dynamic loading and then dissipates. The postcyclic behavior of low-plasticity silt was investigated in this research for materials obtained from the Mississippi River Valley. The experimental program involved specimen preparation using a slurry consolidation approach. A special technique was developed for specimen movement, reducing the testing program time by half. Both static and cyclic triaxial tests were conducted to confirm the ability to prepare replica specimens. In order to characterize the monotonic behavior, triaxial tests were conducted to determine the effective friction angle, critical state line, and normalized behavior. Then specimens were subjected to cyclic loading to develop the liquefaction curve. After full liquefaction, excess pore pressure was dissipated until various reconsolidation levels. The effect of full liquefaction on the permeability and compressibility was studied. The variation in postcyclic shear strength and stiffness with reconsolidation level and the effect of apparent consolidation on shear behavior were also discussed. The critical state lines for the pre- and postliquefaction conditions were compared and found to be not parallel. After limited liquefaction, two unique conditions were tested, at no reconsolidation and at full reconsolidation. The shear strength and stiffness changed significantly at an excess pore pressure ratio greater than 0.70. The experimental program culminated with the study of the effect of plasticity on the pre- and postcyclic shear behavior. Silt-bentonite mixtures resulted in modified plasticity and the transformation from a dilative to a plastic behavior were captured at relatively low plasticity (PI > 6)--Abstract, page iii.

Advisor(s)

Luna, Ronaldo

Committee Member(s)

Kwon, Oh-Sung
Rogers, J. David
Ge, Yu-Ning (Louis)
Stephenson, Richard Wesley

Department(s)

Civil, Architectural and Environmental Engineering

Degree Name

Ph. D. in Civil Engineering

Sponsor(s)

China Scholarship Council

Publisher

Missouri University of Science and Technology

Publication Date

Spring 2011

Pagination

xxiii, 232 pages

Note about bibliography

Includes bibliographical references (pages 223-231).

Geographic Coverage

Mississippi River Valley

Rights

© 2011 Shuying Wang, All rights reserved.

Document Type

Dissertation - Open Access

File Type

text

Language

English

Subject Headings

Plasticity -- Mathematical modelsShear strength of soils -- TestingSilt -- Mississippi River ValleySoil liquefaction -- Mathematical models

Thesis Number

T 9787

Print OCLC #

775789095

Electronic OCLC #

720654019

Recommended Citation

Wang, Shuying, "Postcyclic behavior of low-plasticity silt" (2011). Doctoral Dissertations. 2009.
https://scholarsmine.mst.edu/doctoral_dissertations/2009